Thursday, February 27, 2014

This has to do with some theories that say our universe is a large computer simulation. I've written about that in part of a post here . I've posted it on Facebook. Basically it is a theory that says that the universe that we observe all around us is actually a computer simulation. Before you think I'm crazy some respected scientists take this serious. This idea has also been thought about for years by various philosophers. You can find this all over the net if you do a quick Google on computer simulated universe, here, here,here. If you checked some of these you will see I'm not completely crazy. Recently I've read that there is now a possible experimental test to see if this might be true. The idea is here. It is basically based on patterns observed in lattice Quantum ChromoDynamics (QCD) calculations that come from computer simulations of the reactions between quarks and gluons. QCD is the best model that we have for describing the strong nuclear force. This theory has won a least one set of Nobel prizes. They present in their proposal a signature that our universe is a computer simulation that might be observed in the cosmic microwave background (CMB).

So the story has a group of physics and philosophers talking about this idea and a group of theoreticians presenting this idea about an experimental test. Because of the fame of various participants this meeting and what is discussed is presented in various media outlets. But for some reason, the large media also begin to pick up on this story and its on the front page of the New York Times or maybe the Guardian to give it an international flavor. Then again for some reason it gets on CNN. The other large large networks pick it up and broadcast what the scientists and philosophers were talking about. Now again somehow various fundamentalist religious groups pick up on this computer simulated universe story.

Quick idea about a scifi book that could become a movie. It follows along the lines of what has happened when some large new particle accelerator comes online, in that the accelerator will make a black hole and eat up the earth. That kind of nonsense. So anyways the fundamentalists get all upset that scientists think that they can test to see if God exists. Some start to preach that this is blasphemous or something like that. This concept begins to pick up across the nation. Some of the religious folks pick this up as a possible proof of Intelligent Design but that we are not in a computer simulation. Anyways this all leads to more discussion about science and religion and there place in public schools.

In the movie we have a grad student in a theory group at a large University working on the state of the art lattice QCD calculations. One of the possible outcomes is to get patterns in the calculations that could shown up in the newest CMB data. He or she meets another grad student in computer science whose father is one of the big fundamental group's minister. The computer science student is interested in the limits of what is computable. These two students meet and are attracted to each other. So the movie then plays along these lines. The rest of the book can be filled in with whatever I sort of feel like or if its a movie what the executive producers wants. I think it could be a neat movie.

Saturday, February 15, 2014

The multiverse is a current area of research in theoretical physics. It has generated a wide range of public interest due to its nature of describing our universe as being one of possibily an infinity of other universes, each with physics that maybe similar to ours or maybe widely different than ours. Its unclear to me where the idea of the multiverse started in modern theoretical physics. Anyways a problem with it as far as I can tell from reading about it in a variety of places, is that it lacks predictions that can be tested by data. Here I mean I would like to see a graph of some sort of experimental data along with a curve from a theory model that is related to the data. String/m-theory also has this problem with having a graph of data and theory predictions. In reading Peter Woit's Not Even Wrong blog http://www.math.columbia.edu/~woit/wordpress/
there was a mention of an article about predictions of the multiverse, that article is by Yasunori Nomura a theoretical physicist at UC Berkeleyhttp://quantumfrontiers.com/2014/02/13/making-predictions-in-the-multiverse/. I asked a question to the author about his predictions and comparison to data in the comments section of the article. The author was kind enough to provide an understandable answer to my question about data and the theory of the multiverse. My problem is that I don't really understand the details of some of the physics underlying the answer. Basically he gives the following as results, predictions or consequences of the model(s) to experiment:

1). "the most significant observational “evidence” for the multiverse is the value of vacuum energy."2). The curvature of the universe. He mentions that a positive curvature would rule out the multiverse. "Interestingly, a discovery of a wrong sign, i.e. positive, curvature would falsify the multiverse as we think now, and exploration of curvature might also give us information about possible measures in the multiverse (see e.g. http://arxiv.org/abs/arXiv:1203.6876)."

These are interesting, but not definitive proof of the existence of the multiverse. The problem with the multiverse is that there are almost, if not, an infinity of them. So whatever data we get, other than the positive curvature measurement (I think so far the best measurements say the universe is flat), one can find a universe in the multiverse to match ours. This is the same problem with string/m-theory. Not matter what is measured , with the large number of universes in the string landscape they are sure to find a universe there to match the data. Now this is the situation as far as I can tell. I think some people even try to match the multiverse idea from inflation cosmology with the multiverse idea from string theory. You have a bunch of very bright folks working on these types of models but they have this problem of showing uniqueness. As I saw Steven Weinberg basically say on I believe one of the Fabric of the Cosmos DVD's, is that these types of theories are all we have now and that's why people work on them. As I have posted before, this is a problem, where the question is are people doing physics or metaphysics? This is not a good situation for physicists to get into since it hurts what science stands for and means. This is a question that theoretical physicists really need to think about when developing theories that are not unique. For physics this is using theories, with equations to describe experimental data. One can argue what physical theories really mean. This then becomes an issue for the philosophy of science not physics. This isn't like the issue of the interpretation of quantum mechanics and don't worry what it means just calculate. What quantum mechanics really means is a serious question and has people working on trying to understand its foundations, such as the measurement problem. But in the meantime scientists use quantum mechanics to conduct their research.

These problems as a whole are discussed on a variety of excellent, thoughtful physics blogs listed here

Thursday, February 6, 2014

The physics of our everyday life such as baseballs travelling, the sun shining, electrical circuits, how your car works, things like that are explained well using what is called classical physics. This is using Newton's three laws of motion and his theory of gravity, along with Maxwell's equations to describe electricity, magnetism and light. Regions where some branches of physics get pushed are describing the very small, quantum mechanics, describing the very fast, special relativity, and describing the very massive, general relativity. In talking about physics and infinity I'm talking about pushing physics towards the very small, that is to zero size, and pushing physics to infinitely large, such as is the universe infinitely large? What does it mean to be infinitely small or big? Physics has problems with these issues. An interesting discussion is in the following post:

The post I mentioned is from Max Tegmark, a physicist from MIT who wants to retire the idea of infinity.

The infinitely small I kind of understand, in that as far as I can tell the smallest size that can exist using present physics is the Planck length of 10-35 meters, that's a decimal point followed by 34 zero's then a 1. So space has a finite smallness at least as present physics says. Pretty darn small, an atom is about 10-10 meters. So Planck length is small but not zero. A picky point is that calculus is based on breaking up finite size object into smaller and smaller pieces until they are infinitely small. But physics says that the Planck length is not zero. I suspect that doesn't change what calculus means. Or in other words in calculus proofs for every epsilon that goes to zero, it now instead goes to the Planck length. Still a question, QED says electron's are point particles, so what gives? This I also have talked about here:

The infinitely big I still have a problem with. Our observable universe is about 28 billion light years in diameter, it is BIG. I like how the BBC's Hitchhiker's Guide to the Galaxy TV series talks the universes size. A light years is about 6 trillion miles. One mile = 1.61 km, I don't like miles but folks in the states have no good feel for a kilometer and the distance from the earth to Pluto is about 4 billion miles. So the universe is big but not infinite. That's all we can see, the observable universe. Modern Cosmology from inflation theory says that we live in a multiverse. That is we live in still a larger region, which we cannot observe that has other universe's similar (I'm at a loss for words here, like, similar just doesn't make it) to ours. The only way that I know about how we can observe these other universe's like ours is if in our universe's early history we collided with another universe. As far as I can tell from reading this could possibly be observed in the cosmic microwave background (CMB), that has been observed since the 60' but has been mapped out using satellites recently. As expected newer satellites are getting better resolution images of the CMB. Matching this data to theory is an area of research in Astronomy and Physics. A pretty cool area of research. The idea of a multiverse just kind of bothers me since we may not be able to ever observe them. If a theory has something that we can't observe what does that mean about that theory? I've posted stuff about topic earlier.

Wednesday, February 5, 2014

The question of how life began is a wonderful question for discussion. If you asked this in conversation at a party think about the different answers that you would get. If this were a party of physicist's (these parties can be lots of fun, trust me), here are some answers you might get.

Both are based on the second law of thermodynamics. This law says that the entropy of any closed system stays the same or increases. Entropy is a measure of the disorder of a system. It is also described as the number of ways that a system can be described microscopically without effecting how it is viewed macroscopically. I'm not sure where is the boundary between the two. A closed system is what you expect it to be, its a system where nothing gets in or out of the system.

I look at it in a similar manner. All particle's wants to go to their lowest energy levels. Excited electrons in an atom want to go to the lowest possible energy level that it can while obeying the rules of quantum mechanics. Objects fall since that decreases its gravitational potential energy. Molecules form from atoms that give it the lowest energy configuration of the atoms involved in making the molecule, and so on The molecule is the lowest energy configuration of the combined atoms. Something like this. maybe not as I have expressed it but similar.

This principle of minima or maxima is expressed using the calculus of variations and applied in physics using the principle of least action, sort of explained here along with some philosophical discussion at the end.

Sunday, February 2, 2014

What is the most precious thing a person can sell you? What is your answer?

What do people sell you that is the most precious? Your house? Your old 1965 Ford Mustang? Your jewelry? Your food? Your water, electricity. natural gas, heating oil, cable? Your cellphone and its unlimited access to your friends and relatives, the internet and your business? Their body? What is your answer? Think about it.

My answer is time. The most precious thing that a person sells is their time. A person has one life in which to live. One life and the time we have in our universe. When you take a job you are selling your time to your employer. Your employer is the consumer, they are buying your time. Your precious time, your life. When you hire someone to do something you are buying their time. No matter what the skill you are hiring them for, you are buying their time.

I guess that is also a part of falling in love with someone. You want to spent your time with them. I guess at some point it becomes a shared time. I'm not saying love is a commodity to sell and barter and trade, but its wanting to be with someone else and for the sharing of time and all the experiences that come with it. I don't know how to express this feeling in a romantic way that great writers and poets can do.